Database ConnectPool의 구현...

Koders를 검색하던중 ConnectPool의 구현을 C++의 template기반으로 구현한 소스가 있어 정리해 봤습니다.

유용하게 사용할수 있을것 같습니다.

아래 첨부된 소스의 원형은
   http://www.koders.com/cpp/fid7219F33FFBFD5B5AAEC68184D06F48C0DAAF347C.aspx
에 존재합니다.

#ifdef _MSC_VER
#pragma warning( disable : 4503 4355 4786 4290 )
#endif

#include <string>
#include <map>

class ConnectionID
{
public:
  ConnectionID(
   const std::string& database,
   const std::string& user,
   const std::string& password,
   const std::string& host,
   short port
  ): m_database(database),
     m_user(user),
     m_password(password),
     m_host(host),
     m_port(port)
  {
  }

  friend bool operator <  ( const ConnectionID&, const ConnectionID& );
  friend bool operator == ( const ConnectionID&, const ConnectionID& );
  friend bool operator != ( const ConnectionID&, const ConnectionID& );
 
  const std::string& getDatabase() const { return m_database; }
  const std::string& getUser() const     { return m_user; }
  const std::string& getPassword() const { return m_password; }
  const std::string& getHost() const     { return m_host; }
  short getPort() const                  { return m_port; }
 
private:
  std::string m_database;
  std::string m_user;
  std::string m_password;
  std::string m_host;
  short m_port;
};

inline bool operator < (const ConnectionID& lhs, const ConnectionID& rhs )
{
  if (lhs.m_database < rhs.m_database) return true;
  else if (rhs.m_database < lhs.m_database) return false;
  else if (lhs.m_user < rhs.m_user) return true;
  else if (rhs.m_user < lhs.m_user) return false;
  else if (lhs.m_password < rhs.m_password) return true;
  else if (rhs.m_password < lhs.m_password) return false;
  else if (lhs.m_host < rhs.m_host) return true;
  else if (rhs.m_host < lhs.m_host) return false;
  else if (lhs.m_port < rhs.m_port) return true;
  else if (rhs.m_port < lhs.m_port) return false;
  else return false;
}

inline bool operator == (const ConnectionID& lhs, const ConnectionID& rhs)
{
  return ((lhs.m_database == rhs.m_database) &&
    (lhs.m_user == rhs.m_user) &&
    (lhs.m_password == rhs.m_password) &&
    (lhs.m_host == rhs.m_host) &&
    (lhs.m_port == rhs.m_port));
}

inline bool operator != (const ConnectionID& lhs, const ConnectionID& rhs)
{
  return !(lhs == rhs);
}

// -------------------------------------------------------------------------
template <typename T> class ConnectionPool {
public:
  ConnectionPool( bool usePool = true)
   : m_used( usePool) { }

  T &create( const ConnectionID &id)
  {
   if (!m_used)
    return new T( id);
   else {
    if (m_connections.find( id) == m_connections.end())
     m_connections[id] = Connection( new T(id), 0);
   } m_connections[id].second++;
   return m_connections[id].first;
  }

  bool destroy( T *p)
  {
   if (!m_used)
    delete p;
   else {
    const ConnectionID &id = p->connectionID();
    if (m_connections.find( id) == m_connections.end())
     return false;
    else {
     Connection &c = m_connections[id];
     if (c.first != p)
      return false;
     else {
      ;
     } c.second--;
     if (c.second == 0)
     {
      m_connections.erase( id);
      delete p;
     }
    }
   } return true;
  }

private:
  typedef std::pair<T*, int> Connection;
  typedef std::map<ConnectionID, Connection> Connections;

  Connections m_connections;
  bool m_used;
};

참고로, T 객체의 원형을 다음과 같이 유지해 주면 됩니다.

class T {
public:
   T( const ConnectionID &id)
     : m_connectionID(id) { }
   const ConnectionID& connectionID() { return m_connectionID; }
private:
   ConectionID m_connectionID;
};